Perform studies on the fine specificity of the following manifestations of acquired immunity: humoral antibody; helper function in antibody formation; MIF production, antigen-induced-DNA synthesis; delayed hypersensitivity; and rosette formation. Rleavite affinities (or their equivalents) will be determined for various manifestations of cellular immunity and for helper activity. Studies shall also be undertaken on genetically controlled differences in fine specificity of anti-NP antibodies. The fine specificity of NP-specific T cell rosettes ahall be investigated to determine whether the strain characteristics are present on T cell receptors.